Field of the Invention
The present invention relates generally to a fire and smoke damper and, more particularly, to a spring-activated damper.
In all building environments, it is required to control the progress of fire and smoke throughout the building structure. The structures used to control the progress are defined as "dampers". These units may be only "fire dampers", "smoke dampers", or combination "fire and smoke dampers". Fire dampers have ratings specified in hours--commonly 1.5 hours and three hours. A "normally open" fire damper is installed in an air distribution system and is designed to close automatically upon the detection of heat so as to prevent migratory air flow and restrict the passage of flames from one side of the damper to the other.
Smoke control systems are intended to be activated during the early stages of a fire situation to maintain a "safe" environment by restricting the flow of smoke into exit passageways, or other "safe" designated areas of a building area. All fires produce smoke, which if not controlled, will spread, endangering life and property. Even when a fire is contained within a fire-resistive area, smoke can readily spread to adjacent areas through openings such as ducts and open doors. A smoke damper is a device located in areas such as ceiling and floor ducts to block the egress of smoke into adjacent areas. Conventional arrangements utilize a smoke detector to activate the damper, where the detector is coupled to a motor mechanism to control the operation of the damper. In some situations, however, the motor may fail to operate correctly, allowing the smoke to escape.